System and method for filling reductant tank

ABSTRACT

A method for filling a reductant tank is disclosed. The method includes creating a lower air pressure within the reductant tank than a pressure of an external reductant reservoir using the first valve, the second valve, and the venturi. The method also includes determining a level of a reductant in the reductant tank. The method further includes engaging the tank fill coupling mechanism with the external reductant reservoir. The method includes supplying the reductant from the external reductant reservoir into the reductant tank based on a pressure difference between the air pressure within the reductant tank and the pressure of the external reductant reservoir. The method also includes shutting-off the supply of the reductant based, at least in part, on the level of the reductant in the reductant tank. The method further includes disengaging the tank fill coupling mechanism from the external reductant reservoir.

TECHNICAL FIELD

The present disclosure relates to an aftertreatment system, morespecifically to a system and method for filling a reductant tank of theaftertreatment system.

BACKGROUND

An exhaust aftertreatment system associated with an engine may include areductant supply system for delivery of a reductant into an exhauststream of the engine. The reductant supply system may include a tank forstoring the reductant, a pump, a reductant injector, and reductantdelivery conduits. The reductant delivery conduits may fluidly connectvarious components of the reductant supply system for flow of thereductant therethrough. The reductant from the tank may be supplied tothe reductant injector via the pump.

Reductant tanks generally require periodic refilling. The reductanttanks are refilled using an external reductant reservoir. The externalreductant reservoir includes a pump. The reductant from the externalreductant reservoir is pressurized and introduced into the reductanttank by the pump present at an external location.

U.S. Publication Application Number 2012/279576 describes a motorvehicle includes a tank for storing a liquid reducing agent suppliableto the exhaust system of an internal-combustion engine, and an airdelivery device, by which an excess pressure can be built-up in acushion of air situated in the tank above the reducing agent level. Viathe air delivery device, alternatively, a vacuum is generatable in theair cushion, which vacuum supports feeding of the agent into the tank.Via the vacuum in the air cushion, reducing agent can also be returnedfrom a pipe, which leads the reducing agent to the exhaust system, backinto the tank, and/or additional liquid reducing agent can betransferred from a storage tank by way of a supply duct.

SUMMARY OF THE DISCLOSURE

In one embodiment of the present disclosure, a method for filling areductant tank is disclosed. The method includes connecting an injectorsupply conduit to the reductant tank and an injector. The method alsoincludes providing a driving fluid source in fluid communication withthe reductant tank via a dose driving conduit. The method furtherincludes connecting a purge conduit with the driving fluid source andthe reductant tank. The method includes providing a first valve in fluidcommunication with the reductant tank via the dose driving conduit andthe purge conduit. The method also includes providing a second valve influid communication with the reductant tank via the purge conduit. Themethod further includes providing a venturi in fluid communication withthe first valve and the second valve. The method includes providing atank fill coupling mechanism in fluid communication with the reductanttank via a fill conduit. The method also includes creating a lower airpressure within the reductant tank than a pressure of an externalreductant reservoir using the first valve, the second valve, and theventuri. The method further includes determining a level of a reductantin the reductant tank. The method includes engaging the tank fillcoupling mechanism with the external reductant reservoir. The methodalso includes supplying the reductant from the external reductantreservoir into the reductant tank based on a pressure difference betweenthe air pressure within the reductant tank and the pressure of theexternal reductant reservoir. The method further includes shutting-offthe supply of the reductant based, at least in part, on the level of thereductant in the reductant tank. The method includes disengaging thetank fill coupling mechanism from the external reductant reservoir.

Other features and aspects of this disclosure will be apparent from thefollowing description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an exemplary engine system, according to anembodiment of the disclosure;

FIG. 2 is a schematic view of a reductant supply system associated withan aftertreatment system of the engine system, according to anembodiment of the disclosure; and

FIG. 3 is a flowchart for a method of filling a reductant tank.

DETAILED DESCRIPTION

Various embodiments of the disclosure will now be described withreference to the drawings, wherein like reference numbers refer to likeelements, unless specified otherwise. Referring to FIG. 1, a blockdiagram of an exemplary engine system 100 is illustrated, according toan embodiment of the disclosure. The engine system 100 includes anengine 102, which may be an internal combustion engine such as areciprocating piston engine or a gas turbine engine, for example.According to an embodiment of the disclosure, the engine 102 is a sparkignition engine or a compression ignition engine such as a dieselengine, a homogeneous charge compression ignition engine, or areactivity controlled compression ignition engine, or other compressionignition engine known in the art. The engine 102 may be fueled bygasoline, diesel fuel, biodiesel, dimethyl ether, alcohol, natural gas,propane, hydrogen, combinations thereof, or any other combustion fuelknown in the art.

The engine 102 may include other components such as, a fuel system, anintake system, a drivetrain including a transmission system, and so on.The engine 102 may be used to provide power to any machine including,but not limited to, an on-highway truck, an off-highway truck, an earthmoving machine, an electric generator, and so on. Further, the enginesystem 100 may be associated with an industry including, but not limitedto, transportation, construction, agriculture, forestry, powergeneration, and material handling.

The engine system 100 includes an exhaust aftertreatment system 104fluidly connected to an exhaust manifold of the engine 102. Theaftertreatment system 104 is configured to treat an exhaust gas flow 106exiting the exhaust manifold of the engine 102. The exhaust gas flow 106contains emission compounds that may include Nitrogen Oxides (NOx),unburned hydrocarbons, particulate matter, and/or other combustionproducts known in the art. The aftertreatment system 104 may beconfigured to trap or convert NOx, unburned hydrocarbons, particulatematter, combinations thereof, or other combustion products in theexhaust gas flow 106 before exiting the engine system 100.

The aftertreatment system 104 may include a reductant supply system 108.The reductant supply system 108 is configured to dispense a reductant inthe exhaust gas flow 106. The aftertreatment system 104 may also includea Selective Catalytic Reduction (SCR) module 110 provided downstream ofthe reductant supply system 108. The SCR module 110 is configured toreduce a concentration of NOx in the exhaust gas flow 106. The SCRmodule 110 may include a catalyst for facilitating the reaction,reduction, or removal of NOx from the exhaust gas flow 106 passingthrough the SCR module 110. The SCR module 110 may have a honeycomb orother structure made from or coated with an appropriate material. Thematerial may be an oxide, such as vanadium oxide or tungsten oxide,coated on an appropriate substrate, such as titanium dioxide. The SCRmodule 110 may have a monolithic structure or may include multiple banksbased on system requirements.

According to an embodiment of the disclosure, the aftertreatment system104 may include a filter (not shown), such as, for example, a DieselParticulate Filter (DPF), provided upstream of the SCR module 110. TheDPF may be coated with a suitable catalyst to promote oxidation of anyparticulate matter in the exhaust gas flow 106 that may be trapped inthe DPF. Additionally, in another embodiment, the aftertreatment system104 may further include a Diesel Oxidation Catalyst (DOC). In such anembodiment, the DOC may be positioned upstream of the SCR module 110, inan exhaust flow direction. Alternatively, the aftertreatment system 104may omit the DPF and include only the SCR module 110. In yet anotherembodiment, a combined DPF/SCR catalyst (not shown) may be used.

Further, the aftertreatment system 104 may include one or more NitrousOxide (NOx) sensors 112. The NOx sensors 112 may be located at varyinglocations within the aftertreatment system 104. For example, the NOxsensors 112 may be located upstream and/or downstream of the SCR module110. The NOx sensors 112 may be configured to measure the concentrationof NOx compounds in the exhaust gas flow 106 passing through theaftertreatment system 104. Similarly, other additional sensors, such as,a pressure sensor and a temperature sensor may also be included incontact with the exhaust gas flow 106 without any limitation. Theaftertreatment system 104 disclosed herein is provided as a non-limitingexample. It will be appreciated that the aftertreatment system 104 maybe disposed in various arrangements and/or combinations relative to theexhaust manifold. These and other variations in the aftertreatmentsystem design are possible without deviating from the scope of thedisclosure.

As shown in FIG. 1, the reductant supply system 108 includes a reductanttank 114 and an injector 116 for supplying the reductant in an exhaustconduit 118 of the engine system 100. The reductant tank 114 is providedin fluid communication with the injector 116. The reductant tank 114 isconfigured to store the reductant therein. The reductant may be a fluid,such as, Diesel Exhaust Fluid (DEF). Alternatively, the reductant mayinclude urea, ammonia, or other reducing agent known in the art.Parameters related to the reductant tank 114 such as size, shape,location, and material used may vary according to system design andrequirements.

The exhaust conduit 118 is fluidly connected to the exhaust manifold ofthe engine 102, the injector 116, and the SCR module 110. The exhaustconduit 118 is configured to provide a passage 120 for the exhaust gasflow 106 therethrough. The injector 116 is configured to dispense thereductant into the exhaust gas flow 106. In an embodiment of thedisclosure, the reductant supply system 108 may include one or morepairs of the injectors 116. The number of the injector 116 may varybased on the type of application.

FIG. 2 is a schematic view of the reductant supply system 108, accordingto an embodiment of the disclosure. An injector supply conduit 122 isarranged and configured to fluidly connect the reductant tank 114 andthe injector 116 such that the reductant drawn from the reductant tank114 may be delivered to the injector 116 via the injector supply conduit122. An in-tank filter 124 is provided within the reductant tank 114.The in-tank filter 124 may include, for example, a sock filter or otherfilter configuration known in the art. An in-line filter 126 may bedisposed in the injector supply conduit 122. More particularly, thein-line filter 126 is positioned between the injector 116 and thereductant tank 114. The in-line filter 126 disclosed herein may be anytype of filter known to a person of ordinary skill in the art.

The injector supply conduit 122 may be fluidly connected to a pressuremanifold 128 associated with the injector 116. The pressure manifold 128is provided downstream of the reductant tank 114 and the in-line filter126. The pressure manifold 128 is configured to collect the reductantreceived from the reductant tank 114 and distribute the reductant to theinjector 116. During a dosing operation, a controller 130 may send acontrol signal to open the injector 116 for a predetermined time periodin order to allow the reductant to be injected into the exhaust gas flow106. An injector pressure sensor 132 may be connected to the pressuremanifold 128. The injector pressure sensor 132 is configured to generateand send a signal indicative of an injection pressure of the injector116 to the controller 130.

A driving fluid source 134 is provided in fluid communication with thereductant tank 114. The driving fluid source 134 is configured to supplya driving fluid. In an embodiment of the disclosure, the driving fluidsource 134 may include an air compressor for delivering pressurized air,a storage pressure vessel, or combinations thereof. The air compressormay be any type of known positive displacement compressor or a turbomachine. Alternatively, the driving fluid source 134 may be any othercomponent serving the purpose of supplying a pressurized source of thedriving fluid.

A first valve 136 is provided downstream of the driving fluid source134. The first valve 136 is configured to fluidly connect the drivingfluid source 134 with the reductant tank 114 via a dose driving conduit140 or a purge conduit 142, depending on a configuration of the firstvalve 136. The first valve 136 disclosed herein may be any type of aknown 3-way, 2-position valve configured to connect the driving fluidsource 134 to the dose driving conduit 140 or the purge conduit 142. Inone example, the first valve 136 may be a 3-way, 2-positon ball valve.Alternatively, the first valve 136 may be a 3-way, 3-position valve.

During a reductant dosing operation, the first valve 136 may be in afirst configuration such that the first valve 136 effects fluidcommunication between the driving fluid source 134 and the reductanttank 114 through the dose driving conduit 140 via a valve passage 148.Further, in this configuration, the first valve 136 is configured toblock fluid communication between the driving fluid source 134 and theinjector supply conduit 122 via the purge conduit 142.

During a purge operation, the first valve 136 may be in a secondconfiguration such that the first valve 136 is configured to effectfluid communication between the driving fluid source 134 and thereductant tank 114 via the purge conduit 142 and a valve passage 152,and block fluid communication between the driving fluid source 134 andthe reductant tank 114 via the dose driving conduit 140. Actuation ofthe first valve 136 between the first and second configurations may bedone manually or through the controller 130. The controller 130 mayactuate the first valve 136 via an electrical actuator, such as asolenoid, a pneumatic actuator, a hydraulic actuator, or other actuatorknown in the art. The reductant delivery and purge operations will beexplained in detail later in this section.

The dose driving conduit 140 and the purge conduit 142 may be connectedto a top portion of the reductant tank 114 with respect to gravity. Areductant tank pressure sensor 144 may be connected to the dose drivingconduit 140 and upstream of the reductant tank 114. Further, thereductant tank pressure sensor 144 may be operatively coupled to thecontroller 130. The reductant tank pressure sensor 144 is configured tomeasure the pressure within the reductant tank 114.

Further, the dose driving conduit 140 may include a pressure regulator146 connected downstream of the first valve 136, and in association withthe reductant tank 114. The pressure regulator 146 is configured to, atleast in part, mitigate high pressure spikes in the reductant tank 114.In one embodiment, the pressure regulator 146 may be an electricallycontrolled pressure regulator in operative communication with thecontroller 130.

The purge conduit 142 may include a venturi 150 connected upstream ofthe reductant tank 114. An upstream side of the venturi 150 is fluidlyconnected to the first valve 136. The venturi 150 may include aconverging-diverging nozzle or any other device known in the art forcreating suction from a fluid flow. Further, a suction port 154 of theventuri 150 is fluidly connected to a second valve 138. The second valve138 is provided in series fluid communication with the purge conduit142, such that the second valve 138 is located downstream of the firstvalve 136 and upstream of the reductant tank 114. Operation of thesecond valve 138 may be used to apply suction to the reductant tank 114.The second valve 138 may be embodied as a 2-way valve.

During an operational state of the engine 102, the reductant supplysystem 108 may inject or dose a desired amount of the reductant into theexhaust gas flow 106. The injector 116 may receive the reductant fromthe reductant tank 114. As shown in FIG. 2, the first valve 136 is inthe first configuration. The driving fluid source 134 is configured tointroduce the driving fluid into the reductant tank 114 through thefirst valve 136, via the dose driving conduit 140.

The driving fluid may pressurize the reductant tank 114 to a givenpressure. It should be noted that during the dosing operation, based oncontrol signals received from the controller 130, the second valve 138is in a closed position, so that pressure may build up in the reductanttank 114. In one embodiment, this pressure of the reductant tank 114 maybe approximately equal to a pressure at which the reductant isintroduced by the injector 116 into the exhaust gas flow 106. Thecontroller 130 associated with the reductant supply system 108 may beconfigured to sense the pressure of the pressure manifold 128 and/or theinjection pressure of the injector 116, via the injector pressure sensor132. The controller 130 may be further configured to regulate anoperation of the driving fluid source 134 or the operation of the firstvalve 136 in order to control a quantity of the driving fluid beingintroduced into the reductant tank 114.

The driving fluid introduced within the reductant tank 114 may increasea pressure of the reductant tank 114, further causing the reductantpresent in the reductant tank 114 to enter into the injector supplyconduit 122. The reductant may flow through the in-tank and in-linefilters 122, 124, and flow into the pressure manifold 128. The reductantmay further be introduced by the injector 116 into the exhaust conduit118.

Some quantity of the reductant may be retained in the components of theaftertreatment system 104. For example, the reductant may be retained inthe reductant delivery lines, such as, the injector supply conduit 122.The purge conduit 142 of the reductant supply system 108 is configuredto purge this reductant that is retained within the components of theaftertreatment system 104.

During the purge operation, the second valve 138 is actuated by thecontroller 130 and operates in an open position. The second valve 138may release the pressure built up within the reductant tank 114 and ventthe same to the atmosphere via the valve passage 156. When the pressurein the reductant tank 114 reaches a predetermined pressure value, forexample, approximately 50 kPa, the first valve 136 is actuated by thecontroller 130 to operate in the second configuration. It should benoted that the first valve 136 may be operated in the secondconfiguration for a predetermined time period or until negative pressureis created within the reductant tank 114. The controller 130 may sendcontrol signals to close the first valve 136 thereafter.

In this configuration of the first valve 136, the venturi 150 is influid communication with the driving fluid source 134 via the valvepassage 152. On actuation of the driving fluid source 134, the drivingfluid is delivered to the venturi 150 of the purge conduit 142 via thevalve passage 152. Suction generated at the suction port 154 of theventuri 150 may cause the driving fluid collected in the top portion ofthe reductant tank 114 to be drawn into the valve passage 156 and ventedoutside the reductant tank 114. A negative pressure may be createdwithin the reductant tank 114, thereby drawing fluid from flow passagesof the reductant supply system 108 into the reductant tank 114. Forexample, reductant present in the injector supply conduit 122 may bedrawn into the reductant tank 114 by suction generated at the venturi150, thereby purging the injector supply conduit 122.

Further, during the operation of the machine, a level of the reductantin the reductant tank 114 may decrease, based on usage thereof. A lowlevel of the reductant within the reductant tank 114 may affect aperformance of the aftertreatment system 104. The reductant tank 114 mayinclude a tank level gauge 157. The tank level gauge 157 may determine alevel of the reductant present within the reductant tank 114. In oneembodiment, the tank level gauge 157 may include a float. Alternatively,the tank level gauge 157 may include a sensor, for example, an infraredsensor. The tank level gauge 157 may be communicably coupled to thecontroller 130. The controller 130 may be configured to display thelevel of the reductant present within the reductant tank 114 on adisplay present within an operator cabin, in order to make an operatorof the machine aware of the level of the reductant in the reductant tank114. When the level of the reductant present within the reductant tank114 drops below a pre-determined level, the reductant tank 114 may needto be refilled. The reductant tank 114 is generally filled by anexternal reductant reservoir 164.

The reductant supply system 108 includes a tank fill coupling mechanism158. The tank fill coupling mechanism 158 may include any type of aknown quick connect coupling to provide fluid communicationtherethrough. The tank fill coupling mechanism 158 is connected to thereductant tank 114 via a fill conduit 160. A first end of the fillconduit 160 is connected to the tank fill coupling mechanism 158,whereas a second end protrudes within the reductant tank 114. The tankfill coupling may operate as a plug and play component such that thetank fill coupling mechanism 158 provided on the machine allows forquick and easy coupling with a nozzle (not shown) of the externalreductant reservoir 164.

Further, the second end of the fill conduit 160 is provided with a thirdvalve 162, such that the third valve 162 is disposed within thereductant tank 114. The third valve 162 may be embodied as anyunidirectional valve known in the art, such that fluid flow is allowedinto the reductant tank 114 and prevented out of the reductant tank 114.In one embodiment of the present disclosure, the third valve 162 may bean automatic shut-off valve. The third valve 162 may be coupled to thecontroller 130 such that on receiving control signals from thecontroller 130, the third valve 162 may block fluid flow into thereductant tank 114. The controller 130 may send these control signals tothe third valve 162 when the level of the reductant within the reductanttank 114 exceeds a pre-set level.

The external reductant reservoir 164 is configured to store thereductant therein and serve as a supply for the reductant to thereductant tank 114. A reductant supply conduit 166 and the nozzle areattached to the external reductant reservoir 164. The external reductantreservoir 164 may be selectively connected to the reductant tank 114based on an engagement of the nozzle with the tank fill couplingmechanism 158, allowing for reductant flow from the external reductantreservoir 164, through the reductant supply conduit 166, the nozzle, thetank fill coupling mechanism 158, the fill conduit 160, and into thereductant tank 114. The operation of filling the reductant into thereductant tank 114 will now be explained in detail.

As explained in reference to the purge operation, the second valve 138is actuated by the controller 130, in order to de-pressurize thereductant tank 114. Further, the nozzle of the external reductantreservoir 164 may be connected with the tank fill coupling mechanism158, thereby providing fluid communication between the externalreductant reservoir 164 and the reductant tank 114. Based on the controlsignals from the controller 130, the first valve 136 is actuated tofluidly connect the driving fluid source 134 to the reductant tank 114via the purge conduit 142. The air present within the reductant tank 114may be drawn into the suction port 154 of the venturi 150 via the secondvalve 138 present in the purge conduit 142. Thus, a vacuum or negativepressure is created within the reductant tank 114. The air pressure ofthe reductant tank 114 is lesser than a pressure within the externalreductant reservoir 164.

Due to the pressure difference between the reductant tank 114 and theexternal reductant reservoir 164, the reductant present within theexternal reductant reservoir 164 is drawn into the reductant tank 114,via the reductant supply conduit 166 and the fill conduit 160. In oneembodiment, when the reductant within the reductant tank 114 exceeds thepre-set level, the third valve 162 may receive the control signals fromthe controller 130 to block or shut off fluid communication between thereductant tank 114 and the external reductant reservoir 164. This mayindicate that the reductant tank 114 is filled to the desired level. Thereductant supply conduit 166 may then be disconnected or disengaged fromthe tank fill coupling mechanism 158. The controller 130 may sendcontrol signals to close the first and second valves 136, 138 and/or toturn off a delivery of the driving fluid from the driving fluid source134.

INDUSTRIAL APPLICABILITY

The present disclosure describes a system and method for filling thereductant into the reductant tank 114, based on capabilities of thereductant tank 114 itself. Based on the creation of the low pressurewithin the reductant tank 114, the reductant from the external reductantreservoir 164 is drawn into the reductant tank 114. Thus, the filling ofthe reductant within the reductant tank 114 may be independent of anexternal motive force present at the external reductant reservoir 164.

FIG. 3 is a flowchart for a method 300 of filling the reductant tank114. At step 302, the injector supply conduit 122 is connected to thereductant tank 114 and the injector 116. At step 304, the driving fluidsource 134 is provided in fluid communication with the reductant tank114 via the dose driving conduit 140. At step 306, the purge conduit 142is connected with the driving fluid source 134 and the reductant tank114. At step 308, the first valve 136 is provided in fluid communicationwith the reductant tank 114 via the dose driving conduit 140 and thepurge conduit 142. At step 310, the second valve 138 is provided influid communication with the reductant tank 114 via the purge conduit142. At step 312, the venturi 150 is provided in fluid communicationwith the first and second valves 136, 138. At step 314, the tank fillcoupling mechanism 158 is provided in fluid communication with thereductant tank 114 via the fill conduit 160.

At step 316, the lower air pressure is created within the reductant tank114 than the pressure of the reductant reservoir 164 using the firstvalve 136, the second valve 138, and the venturi 150. At step 318, thetank level gauge 157 is configured to determine the level of thereductant in the reductant tank 114. At step 320, the tank fill couplingmechanism 158 is engaged with the external reductant reservoir 164. Atstep 322, the reductant from the external reductant reservoir 164 issupplied into the reductant tank 114, based on a pressure differencebetween the air pressure within the reductant tank 114 and the pressurewithin the external reductant reservoir 164. At step 324, the supply ofthe reductant is shut-off based, at least in part, on the level of thereductant in the reductant tank 114. At step 326, the tank fill couplingmechanism 158 is disengaged from the external reductant reservoir 164.

The system and method of filling the reductant tank 114 disclosed hereindoes not require the additional motive force for reductant tankrefilling purposes. Further, the system may be easily installed onexisting machines with very few modifications. Also, the reductant tank114 may be easily refilled on a worksite on which the machine isoperating.

While embodiments of the present disclosure have been particularly shownand described with reference to the embodiments above, it will beunderstood by those skilled in the art that various additionalembodiments may be contemplated by the modification of the disclosedmachines, systems and methods without departing from the spirit andscope of what is disclosed. Such embodiments should be understood tofall within the scope of the present disclosure as determined based uponthe claims and any equivalents thereof.

What is claimed is:
 1. A method for filling a reductant tank, the methodcomprising: connecting an injector supply conduit to the reductant tankand an injector; providing a driving fluid source in fluid communicationwith the reductant tank via a dose driving conduit; connecting a purgeconduit with the driving fluid source and the reductant tank; providinga first valve in fluid communication with the reductant tank via thedose driving conduit and the purge conduit; providing a second valve influid communication with the reductant tank via the purge conduit;providing a venturi in fluid communication with the first valve and thesecond valve; providing a tank fill coupling mechanism in fluidcommunication with the reductant tank via a fill conduit; creating alower air pressure within the reductant tank than a pressure of anexternal reductant reservoir using the first valve, the second valve,and the venturi; determining a level of a reductant in the reductanttank; engaging the tank fill coupling mechanism with the externalreductant reservoir; supplying the reductant from the external reductantreservoir into the reductant tank based on a pressure difference betweenthe air pressure within the reductant tank and the pressure of theexternal reductant reservoir; shutting-off the supply of the reductantbased, at least in part, on the level of the reductant in the reductanttank; and disengaging the tank fill coupling mechanism from the externalreductant reservoir.